The present disclosure relates to digital information processing, and particularly to labeling images for information retrieval.
The Internet provides access to a wide variety of resources, for example, video or audio files, or Web pages including content for particular subjects, book articles, or news articles. A search system can select one or more resources in response to receiving a search query that includes one or more search terms or phrases. The search system selects and scores resources based on their relevance to the search query and on their importance relative to other resources to provide search results that link to the selected resources. The search results are typically ordered according to the scores.
The relevance of a resource to a search query can be determined based on text associated with the resource. The text associated with a resource includes text that appears in the resource, text that appears on a same Web page as the resource, and text metadata for the resource. For example, text associated with resources can be compared to a search query to determine measures of relevance for the resources relative to the search query. In turn, the resources are scored based on the comparisons and search results corresponding to the resources are ordered for presentation based on the scores.
Images are an example of resources that can be determined to be relevant to a search query based on text associated with the image. The relevance of an image to the search query can be determined, for example, based on text that appears within a specified proximity of the image. For example, an image that is presented on a Web page and within a specified proximity of the text “football” can be determined to be relevant to the queries “football,” and/or “sports” and referenced in search results for these queries.
While text associated with an image can be used to compute the relevance of the image to a search query, it can sometimes be difficult to determine the relevance of individual words of the text that is associated with the image. For example, an image of a knife may be associated with the text “a wedding cake knife.” Based solely on this text, it can be difficult to determine which of the terms “wedding,” “cake,” and “knife” is more relevant to the content of the image. Therefore, the image of the knife may be improperly identified as being a relevant image for the queries “cake” or “wedding cake” even though a cake does not appear in the image. Similarly, some text that is identified as being associated with the image based, for example, based on its proximity to the image, may be text that was included in the Web page to describe other content of the Web page (e.g., another image in the Web page).